


So you want to have a child

by SesuRescue (Kigachan)



Category: Undertale (Video Game)
Genre: Fertility Planning, Is there a plot here?, M/M, Mpreg, Skeleton Pregnancy (Undertale), Slice of Life, This fic is less "I'm pregnant!" and more "I'm trying to get pregnant!", a small dash of anxiety, ecto-body
Language: English
Status: Completed
Published: 2018-12-25
Updated: 2018-12-25
Packaged: 2019-09-26 18:52:53
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,068
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17147210
Author URL: https://archiveofourown.org/users/Kigachan/pseuds/SesuRescue
Summary: Papyrus and Grillby want to start a family!AKA, A Slice of Life pregnancy fic where the topic is family planning!





	So you want to have a child

**Author's Note:**

  * For [MoonRuiner](https://archiveofourown.org/users/MoonRuiner/gifts).



> This is for Undertail Secret Santa!
> 
> I wanted to stay inside my comfort zone, yet still hit the topics you wished for in your requests, so I hope that you find this fic to your liking! Happy Holidays!

Grillby sighed as he got to his feet, patting his hands against his dirtied rag. It was a day off for him, and he had decided to spend at least a portion of it cleaning up soot from the crevices and corners of his and Papyrus’s shared apartment. He had been at it for the better part of the morning, and he was pretty happy with the progress he had made. The place usually received the Papyrus brand daily scrub-down and cleaning after sentry duty, but the soot in particular built up fast and was hard to ignore. Even just one or two days of failing to look after it left the floors with a noticeable grey sheen to them.

He didn’t usually clean the house, but Grillby didn't mind picking up the duty today, especially in the current situation. Papyrus was off at the Royal Scientist’s (Al, was it?) lab, getting his SOUL checked for any fertility issues. Grillby didn’t want to add the additional stress of cleaning onto that, but knowing his luck, Papyrus would probably just find something else to nitpick to keep his mind off whatever the Royal Scientist concurred.

The two of them had been trying to have a child for a few months now with little success. At first, Grillby didn’t have any particular feelings about children. The small rabbit children he had run into in Snowdin were nice and pleasant enough, but they never spurred any urge within him to have his own. Then, he met Papyrus.

Papyrus’s thoughts on the matter had come out slowly at first. A coo here at a small monster child, a small sigh there when glancing at baby clothing in the Item Shop window. After they started dating and becoming more serious the hints were more apparent, until shortly after soul bonding Papyrus sat Grillby down on the couch and asked him if he wanted children. Grillby said he was unsure, and Papyrus urged him to think on it.

Grillby figured that it would be easy to just go along with Papyrus’s whims, but a small, nagging part of him knew it wouldn’t be fair if he wasn’t 100% convinced. So he thought on it and thought some more, and the more he thought about it, the more he realized that he rather liked the idea of helping to bring a monster into the world, especially if it was with Papyrus. Their child could possibly be as cute and steadfast as Papyrus or have a strong work ethic like him. Or, maybe their child could be someone wholly different that didn’t resemble either of them! The possibilities were endless, but he knew that no matter what, he and Papyrus would spoil whatever adorable monster came out of a result of their love together.

That thought helped to solidify Grillby’s stance, and he agreed to start trying for a kid with Papyrus. It would be easy; all it took was for both parties to want a child, and it would happen, he thought! But, well…

Grillby gripped the rag and took a deep breath to even out his worrying flames. He needed to find another distraction, or else he’d go crazy with anticipation. Of course, this couldn’t have been more nerve-wracking than whatever Papyrus was going through, especially if the news was--

No, he needed to stop that train of thought right there at the station.

Distraction. Cleaning. There was still more he could clean: the oven, underneath the fridge. Before he could figure out which place to tackle first, he heard the jingling of keys near the front door. His flames perked up at the sound, and he went to greet Papyrus when the door opened, revealing his adorable, disheveled mate. His arms were full of heavy-looking textbooks, and the slight hitch to his breath told Grillby that he exerted himself much more than his magic could keep up, which was a rare occurrence in and of itself.

“...Did you...run all the way from Hotland?” Grillby asked, hoping that his guess was off the mark.

Papyrus slipped off his boots and nudged them neatly into place with his foot. “I Did!” Dammit. “I couldn’t wait to get home!”

Grillby watched as Papyrus sat the books down on the coffee table, and he saw that a few of them had ‘pregnancy’ in the title. Should he take that to mean that Papyrus was okay? Well, it was probably safe enough to ask how the examination went, so he did.

“It was--” Papyrus paused to place a finger to his face as he tried to find the right words-- "Enlightening! I will tell you all about it, but first!” Grillby yelped as Papyrus pulled him in close and pinched his behind. “Let’s go to the bedroom!”

“...Should I clean up first? I’m a little dirty.” Grillby gestured to his soot-covered front.

“Perfectly fine, you can dust off later! Come, copulation awaits!”

Chuckling, Grillby followed Papyrus to the bedroom, shedding his shirt and pants as he went until he was just in his underwear when he reached the bed. He didn’t give Papyrus a chance to comment on the slovenly act, pushing him playfully onto the bed before following him. He brushed his mouth to Papyrus’s teeth and heaved out a soft groan when a cool ectoplasmic tongue probed at his flames.

“...You’re very eager today. I’m guessing the news was positive,” Grillby murmured before opening his mouth to Papyrus’s explorations. They made out lightly, much softer than their usual last-minute romps went, and Grillby took the opportunity to get Papyrus out of his clothes. His fingers blindly fiddled with the buttons on Papyrus’s shirt, and only after he managed to get the last button free did he allow his hand to wander over the soft conjured flesh. “... How do you want it today?”

Papyrus hummed, lifting his lower half so Grillby could slide off his underwear. “I believe that on my back is still the best way to achieve a successful conception! Nine out of ten monsters agree!”

Grillby paused in the midst of going to grab the lube and looked back at Papyrus. “... Don't tell me you took a survey.”

“Of course, I did!”

“...Oh my god.” Grillby could just picture it too: Papyrus in his sentry uniform with a clipboard flagging down monsters. Did Snowdin even have that many mothers? Papyrus wouldn’t have gone all the way to Hotland and New Home to find more monsters, would he? Shaking his head with a small smile, Grillby continued on his quest for the lube. He grabbed the small bottle off the nightstand and squirted what he needed into his palm. “... You're something else, you know that?”

“You decided to bond with me,” Papyrus pointed out.

Grillby placed a hand on Papyrus's leg with a smile. “...And I would do it again in a heartbeat.”

After prepping Papyrus for insertion, Grillby lined himself up with Papyrus and slowly pushed into his entrance. As he worked to sheath himself, Papyrus wrapped his legs around Grillby's hips with a whimper. “I love this part the best,” he sighed wistfully, running a hand down Grillby's chest.

“...We haven't even touched SOULs yet,” Grillby laughed, repositioning himself so that his torso was hovering over Papyrus's. He began to move slowly at first but picked up the pace as he felt Papyrus open up for him.

Even though the two of them had increased how often they made love for conception purposes, it still felt like each time was new, fresh, as if they had never touched before. Grillby couldn't get enough of Papyrus's body, his moans, his adorable facial expressions, and they never failed to get Grillby excited. However, he couldn't stop the idle parts of his brain from thinking over their previous conversation. “... Papyrus.”

“ _Haahn_? W-what's up?”

“...Who was it?”

“Huh?”

“The one monster that didn't agree?”

“Ahh, it was--oh god, move like that again, please--it was…the innkeeper. She thinks that the hands and knees position is-- _yesss--_ is better.”

“... Well, she does have three kids.”

“--Triplets! I bet it was just luck,” Papyrus said. He snaked his arms around Grillby's neck and summoned his SOUL between them. The pale organ was dripping in Papyrus's magic, and Grillby summoned his in response. “Ready?”

After one mind-blowing orgasm, Papyrus and Grillby retired to the living room to check out the books that Papyrus brought home. Grillby laid on the couch, legs propped up in Papyrus’s lap as he flipped through a textbook called, _So you want to have a child, and other questions about fertility_. Apparently, this whole getting pregnant business was much more complicated than he had previously thought. According to the few pages he managed to read all the way through, children could be only be conceived (along with both parent’s intent) within a certain part of a monster’s mating cycle. For some monsters it was easy to track their cycle, but for the two of them--

“...How does a monster even know when they’re ovulating?” Grillby asked.

Papyrus looked up from his own textbook--Well, more of a manual, really. It was much smaller than the other books here, and a quick glance at the cover told Grillby that this book wasn’t directed towards the hopeful carrier, but rather the giving half of the couple. Wait, why wasn’t he reading that one?-- and hummed thoughtfully.

“Well, according to Dr. Alphys it’s different for every monster. For the more furry-type monsters, they have physical tells, I think? I saw it briefly in a book when we were trying to figure out my body’s specifics, you know since skeletons are an enigma at this point in the medical field.”

“...Right,” Grillby nodded. Papyrus and Sans were the only skeleton-type monsters he met, and as far as he knew, they were the only two currently in the Underground. “So did you figure out yours?”

“I think so! I seem to have the closest symptoms to incorporeal monsters, like ghosts. Turns out, the weird slimy film that covers my SOUL every now and again is actually part of my ovulation!”

“...Wait, those were days we chose not to have sex, weren’t they? Since we weren’t sure about it...”

“Correct! We could’ve already been pregnant this whole time if we had just ignored it!” Papyrus brought a hand to his forehead and let out a dramatic sigh as he leaned back against the couch cushions.

Grillby shifted his legs in Papyrus’s lap, careful not to knock over anything as he let the information settle in his head. To think it was under their nose the entire time. “...Okay, so we just need to have sex when your SOUL is excreting that film, and then you’ll get pregnant?”

“In theory, yes, but I still don’t think it’s as easy as that.” Papyrus tapped a hand against Grillby’s legs in a request, and Grillby lifted his legs. Papyrus slipped out from underneath and repositioned himself so that he sat on the floor near Grillby. His spine was flush with the couch, and Grillby had to resist the urge to run his fingers over Papyrus’s smooth neck bones: they did _just_ have sex, after all.  

He had been so focused on the bones in front of him that he almost jumped when Papyrus suddenly made a sound similar to a monster clearing their throat. Papyrus giggled before holding up his book for Grillby to read. “Check out this page here.”

Shifting to his side, Grillby perched his head over Papyrus’s shoulder to look at the book. “... ' _Diet restriction for healthy magic?’_ I don’t understand.”

“It seems like the magic we contribute towards conception might be affected by our food diets!”

“...Is that so.”

Papyrus nodded. “Yes! It looks like healthy foods are better for conception, such as fruits and vegetables.”

“...Ah.” Grillby adjusted his glasses so he could read better and took a hard look at the page displayed. The food Papyrus mentioned were, in fact, in the section titled ‘ _Foods good for the child!’_. Curious, Grillby looked at the other side of the page, where it listed foods not fit for consumption. His eyes widened as he went down the list. “...I’m not supposed to eat fried foods...certain types of meat...wait, Papyrus, this says I can’t drink alcohol.”

“That’s correct!”

“...I’m made of fire,” Grillby deadpanned. “That one is going to be a little difficult.”

“Oh, right,” Papyrus said, looking a little sheepish. “Well, that one we can probably ignore, but the rest might be viable!”

“...You just want me to change my diet in general, don’t you?”

“I mean--!” Papyrus reached behind him, placing his free hand on Grillby’s cheek. He turned his hand upside down and leaned back so that Grillby’s face was in smooching range, then pressed his teeth gently to the side of his face. “It’s not that I want you to completely change your diet because grease is gross and might make your restaurant’s food taste better--”

“...That’s a pretty low blow, don’t you think?” Grillby grumbled.

“--But think about it, it’ll only be for a few weeks and then after we get pregnant you can go back to normal!”

Grillby closed his eyes, taking in a deep breath and letting it out. He really didn’t want to change up what he consumed. He had been eating the same thing for so long that he wasn’t sure what his body would react if he ate something new. Plus, fruits and vegetables?? Were there any of those that he could eat without any trouble?

He felt Papyrus’s expectant gaze from behind his flames. It would be the worst, but Papyrus was right; only a few weeks, then he could eat whatever he wanted.

“...Alright, I’ll do it.”

The next morning Grillby woke up at his regular time (A few hours after Papyrus normally got out of bed) and went to make breakfast, but when he arrived at the kitchen he found a bowl of oatmeal and a banana waiting for him on the dining table. He had been a little dubious about the oatmeal, but a quick dip of his fingers confirmed to him that there was no water present, which meant it must’ve been made with milk instead.

After breakfast, he headed down to his restaurant to open for the day. Surprisingly, Red Bird had instantly noticed the change in his demeanor.

“Eat something different today?” they asked. “Your flames are different.”

Grillby nodded. “...New diet.” After looking to make sure no one needed him, Grillby bent down so that he was at Red Bird’s height. “...I’m not sure if Papyrus wants to keep it a secret or not, but we’ve been trying for a kid recently.”

“Secret?” Red Bird chuckled into their drink. “I’m pretty sure everyone this side of Hotland knows already. He’s not exactly subtle.”

“...Ah.” Grillby wasn’t sure why he was surprised; Papyrus _did_ say he took a survey. Grillby would’ve thought that meant asking them in privacy, but knowing Papyrus, he most likely just asked them in the street. He fought the urge to cover his face. “...Papyrus thinks that if I change my diet it’ll help.”

“Maybe. But also maybe not. In any case, try not to hurt yourself, okay?”

“...Okay, thank you.” Grillby gave Red Bird a smile before retreating back to his usual stance. It was different getting advice from his patrons as opposed to the other way around. Different, but definitely appreciated.

Over the day Red Bird’s concern went to the back of his mind, and soon he was done for the night. He headed back to his apartment after closing up the restaurant. Papyrus had already gone to sleep so it was quiet and nearly dark, save for the small light above the stove. Using his flames to lead the way, Grillby dodged the furniture to reach the kitchen, and when he opened the fridge he noticed a small container on the bottom shelf with his name on it.

“...Oh, Papyrus,” Grillby sighed pleasantly to himself, finding a decent portion of spaghetti and some sort of green vegetable. Until now, he hadn’t had a chance to try Papyrus’s ‘World Famous’ spaghetti, which both Papyrus and Sans had talked up in different ways. At least with this diet, he could experience all of Papyrus’s cooking talents. With that thought in mind, Grillby eagerly popped the container into the microwave and waited for the fabled dish.

It was, in Grillby’s humble opinion, completely indescribable.

* * *

 A week passed with no incident, and when week two came around Grillby noticed that Papyrus observing his SOUL for signs of ovulation. It would’ve been a simple harmless thing that Grillby wouldn’t have thought twice about if it weren’t so...excessive.

The first time Grillby took note of it was on a Thursday. He had left his mid-evening snack at home, and since he didn’t have any suitable food in his restaurant to comply with his diet, Grillby had left Sans in charge while he ran to retrieve it. He had barely gotten through the door when he saw Papyrus sitting on the couch, staring intently at his SOUL curled up in his hands.

“...Oh--sorry, did I interrupt something?” Grillby asked, shutting the door behind him quickly to respect Papyrus’s privacy.

“No, no it’s fine.” Papyrus stood and made his way to Grillby before promptly shoving his SOUL into Grillby’s face. “Do you think it started filming yet?? I can’t tell.”

“...I--what?” Grillby took a step back. He briefly flitted his eyes down to Papyrus’s SOUL. “...It looks the same as it did a week ago,” he said.

“Nuts, not yet I guess.” Papyrus dispelled his SOUL and went back to the couch. Grillby gave Papyrus a quick once-over to make sure he was okay, then he went to the kitchen to retrieve his snack. On the way out the door, he noticed a small glow out of the corner of his eye, and he didn’t even have to turn around to know that Papyrus was looking at his SOUL, again.

The behavior persisted well into the weekend, and it wasn’t until Grillby caught Papyrus standing in the middle of one of his puzzles with his SOUL out did he intervene. He had been on his way to the docks for a supplies trip, but when he saw Papyrus he quickly scrambled over to him and shoved Papyrus’s SOUL into his jacket.

“...Papyrus, that is highly inappropriate,” Grillby lectured, out of breath. “What if someone saw?”

“Everyone already knows I want to get pregnant so it’s fine!” Papyrus chirped. “Besides, no one is going to see me all the way out here.”

Grillby bit his metaphorical tongue, deciding not to mention that he _had,_ in fact, seen him, and instead heaved out a sigh. “...Just be careful, alright.”

“You got it!” Papyrus saluted.

Just when Grillby had thought things were finally settling down, ovulation day came. It was early, about an hour before he usually opened the bar for the day. He had been in the process of wiping down the tables when a forceful knocking on the front door had shocked him. He directed his attention to the door. The curtains prevented him from seeing exactly who was at the door, but that tall silhouette was unmistakable. Placing his cleaning rag on the table, Grillby went to the door and opened it.

“...Papyrus, I wasn’t expecting to…see you here...” He trailed off as Papyrus quickly stepped into the restaurant and locked the door behind him. Grillby watched as Papyrus paced back and forth in the doorway, hands clutched to his chest and a perplexed look on his face. “...Are you alright?”

“Yes!” Papyrus responded automatically. “Uh, well...no.” His brow furrowed. “Maybe? I--well my ovulation cycle started!” He blurted out.

Oh. “...Oh,” Grillby said. “...Should we head home, or…”

“That would take too long, we need to start right away!”

“...But…” Grillby took in Papyrus’s resolute expression, and he knew that Papyrus was going to get his way no matter what. Sighing, Grillby walked over to his bar counter and pulled out a flat piece of paper from his shelf of supplies. He took a marker and quickly scribbled out a message alerting his patrons that his shop was closed for a small emergency and taped the paper to the door. He turned to address Papyrus, but his mind stuttered when he found the other splayed out on the bar counter, clothing already ripped off and thrown to the floor and SOUL displayed.

“Are you done?” Papyrus said sensually. He dragged his fingertips from the base of his femur to just below his pelvis with a soft sigh, and the pale sheen of his ectoplasmic flesh followed. Fluttering his eye-lights in Grillby’s direction, Papyrus threw his head back and moaned. “Don’t leave me hanging, big boy.”

“...Papyrus…” Grillby took small, purposeful steps to the counter. His expression was blank as he brushed his fingers against Papyrus’s knee, and he received a groan in response. Without any warning, Grillby scooped Papyrus up into his arms and deposited him safely onto the floor.

“G-g-grillby!” Papyrus sputtered, flailing his limbs into the air as the cold hit him all at once. “Why did you do that?!?”

“...People eat there,” Grillby said as he slipped to the floor between Papyrus’s legs. He pulled his bowtie loose from his neck, and when that was done he unbuttoned his waistcoat, all the while continuing to scold Papyrus. “...Do you know how hard it is to sanitize a counter after monster fluids get on it? I adhere to a very strong health code, and ovulation or not, I’m not able to risk my restaurant for sex.”

“Sorry, I didn’t know.”

Grillby sighed as he freed his boner from his pants. “...We usually do it in the bedroom or on the couch, so I’m not surprised it never came up. Luckily, the floor is easy to clean again.” He pressed a finger against Papyrus’s entrance, surprised that it was already wet. “...That excited already?”

“I…thinkyou’rereallyhotwhenyou’reangry.” Papyrus hid his head in his hands and mumbled.

“...What?”

“I SAID, I think you’re really hot when you’re angry, okay??” Papyrus screeched, skull growing orange from embarrassment.

Grillby chuckled as he lifted Papyrus’s leg to his shoulder. “...I see. I’ll make sure to keep that in mind for the future. For now, how about I show you all the other ways that I can turn you on?”

“Oh, yes please!”

Despite their best efforts at keeping quiet, someone (Probably Drunk Bun with her sharp hearing) caught wind of what they were doing, and the next day Grillby could feel the eyes of his customers following him as he served food and drinks. Eventually, Sans spoke up.

“heard you had some fun here last night.”

Grillby’s flames sparked wildly, tossing off small bits of fire in every direction as he struggled to rein in his emotions. “...I can explain--”

Sans put up a hand to interrupt. “it’s alright, none of us really mind; we know all about it.”

Was his bedroom life just common knowledge for all of Snowdin now? Grillby took out a shot glass and poured himself a whiskey. Sans watched him down the glass passively and took a swig from his own drink. “so did it work?”

Before Grillby could answer, his phone buzzed several times in his pocket. “...Sorry, one second,” He said, pulling out his phone. He unlocked the screen to see several messages from Papyrus, all laden with various heart and crying emojis. Confused, he scrolled up to the previous messages and saw one with an image attached. He opened the image and immediately closed it as a large picture of Papyrus’s soul came up. “...Papyrus..!”

“huh? what’d he do?”

“...He...wait.” Steeling his nerves, Grillby opened up the image again. Papyrus wouldn’t send a picture of his SOUL for no reason, so Grillby took a moment to look at it fully. It was pale as usual, but in the very center, there was a very tiny splash of orange. The metaphorical gears in Grillby’s head turned as he processed the image, and he scrolled to the bottom where there was a message from Papyrus:

_GRILLBY LOOK! WE DID IT!_

“...Ah, I’m a father,” he muttered with awe.

Then, he passed out.

**Author's Note:**

> Thank you for reading! I appreciate all forms of kudos/comments/love, and if you're over 18, you can follow me on [ Twitter ](https://twitter.com/sesurescue) or [ PillowFort ](https://www.pillowfort.io/SesuRescue)!


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